Virtual Memory

The virtual memory is a technique that is used to provide the storage devices like harddisk of a computer to serve as a level in the memory system. It also prevents program running on the same system from modifying each other data. Virtual memory is used in large computers and allows them to act as the main memory is larger than it actually is.

In virtual memory the logical address of the data is different from the actual physical address. Whenever an address is referred by the CPU, it is mapped from the virtual memory to the physical memory. The hardware in the computer system automatically handles the mapping process.

Address Space and Memory Space

Virtual addresses are the addresses used by the programmer and the set of these addresses is known as address space. The physical address is the address in the main memory and the set of these addresses is known as memory space. The address space in the system can be larger than the memory space with the help of virtual memory.

Only a part of the program that is active in the main memory is loaded into the virtual memory by the operating system. When a memory reference is requested by the active part, the effective address is resolved by the CPU as if there was no virtual memory present in the system. However, the effective address is sent to a memory map instead of directly being sent to the main memory. The memory map is the part of the virtual memory hardware that is used for translating the virtual address to physical address.

Paging and segmentation are the two techniques implemented by the virtual memory for translating the logical addresses into the physical addresses. Paging is a hardware-oriented technique that allows large program to run on the computers that have small memories.

Transtutors.com is the leading provider of the Homework Help and AssignmentHelp for all levels. Our team of experts thrives to provide only original and plagiarism free content for homework help and assignment help. With us you can be rest assured that all the homework help and assignment help provided will come with good number of references.